[seL4] Bitfield generator EBNF grammar

Hey guys,

I've been attempting to put together some rust bindings for the seL4 fault handling mechanisms, and I'm afraid the bitfield generator is driving me a bit up a wall at this point. I'd like to find a concise grammar for the language so I can better understand how bitfield_gen.py works, but there doesn't seem to be any explicit BNF for it anywhere.

Is there a paper I should be reading or a reference guide somewhere that would help?

Thanks!